NEW YORK -- As one of the core members of the Mets team that gave hope to New York City following the terrorist attacks of Sept. 11, 2001, Mike Piazza has visited countless firehouses over the years to meet first responders from that day. Three weeks ago, during a spell in town, Piazza traveled to Engine 280/Ladder 132 in Brooklyn.

Each time he does something like this, Piazza finds himself floored all over again at the humanity he encounters.

“They ran into those buildings,” Piazza said Monday, prior to a remembrance ceremony at Citi Field. “Think about it for a second. All of us would be running away. After you see what’s going on, it’s kind of a weird thought to think about, that you’re going to die. You’re probably going to die. And they didn’t care. They went there to try to save people.”

Talking to Piazza about the events and aftermath of 9/11 means seeing that era through his eyes, with all the vibrancy he still does. Back in Queens on Monday, Piazza, John Franco and Al Leiter took part in a pregame ceremony that included ceremonial first pitches from emergency servicemen and women, a national anthem by the NYPD’s Makiah Brown, a color guard featuring six New York City service departments and more.

During the game, Mets players wore the caps of the FDNY, NYPD, Port Authority Police Department, Department of Sanitation and Department of Correction -- just as they famously did on Sept. 21, 2001, when Piazza homered in the first game in New York following the attacks.

“I think it’s a reminder of the responsibility we have in sports -- baseball, in this case,” said Mets manager Buck Showalter, whose upbringing included a father and two uncles who served in World War II. “There’s a rallying point there … anything that brought back some form of normalcy in our lives.”

In the immediate aftermath of 9/11, Piazza joined Franco, Leiter, Todd Zeile, Bobby Valentine and so many others who focused their time and efforts on those running rescue efforts. Time dulls nearly everything, but for Piazza, not this. He still considers such visits crucial, both in old ways and new ones. Increasingly, Piazza finds himself encountering folks who were not alive for 9/11, or who were too young to remember the day. Part of his current mission is to educate young people -- including his own children -- about it.

“The way we came together that week as a city, as a country, as families, is, I hope, the way we enlighten or teach the next generation going forward,” Piazza said.

In a perfect world, the Hall of Famer added, Sept. 11 will become a federal holiday set aside for remembrance, in much the same way Memorial Day is now. The Mets and Yankees could even have a role, perhaps by playing each other every year on that date.

But even if that never happens, the local teams will continue to do their part, using players like Piazza to help spread the message of remembrance. What the Mets accomplished on Sept. 21, 2001 -- beating back anxiety to make a game happen, wearing first responder caps despite opposition to the idea, winning in dramatic fashion on Piazza’s homer -- remains an intrinsic part of the story of that time.

Others will help. In recent years, first baseman Pete Alonso has shouldered that responsibility, despite the fact that he was a 6-year-old elementary school student in Florida when the attacks occurred. On Monday, Alonso wore custom cleats from Lucia Footwear to honor Answer the Call, an organization that provides financial assistance and support to families of fallen first responders. Alonso and his wife, Haley, donated $10,000 to Answer the Call, invited 50 guests to the game and planned to auction the cleats to raise additional funds.

“This organization, going forward, it will always be part of us,” Piazza said of the Mets and Sept. 11. “It could be 50 years from now -- I know this organization’s going to honor 9/11, because that’s what we do. Because it affected us personally. But also, it was symbolic of our relationship with this community and with those who protect us.”